I. Field of the Invention
The present invention pertains generally to catalysts and more specifically to electrocatalysts, hydrogenation catalysts, hydrocracking catalysts and hydrogen oxidation catalysts.
II. Description of the Background
A fuel cell is an electrochemical device in which chemical energy of a reaction is converted into low voltage electrical energy. Fuel cells have many potential applications, such as supplying power for vehicles, replacing steam turbines and remote power supply applications.
The major components of a fuel cell include an anode for hydrogen oxidation and a cathode for oxygen reduction. The anode and cathode are typically positioned in a cell with an electrolyte. In an alkaline fuel cell, the anode is for hydrogen oxidation and a the cathode for oxygen reduction. Reactants are usually fed through a porous anode and cathode and brought into surface contact with the electrolytic solution. To speed up reactions at the surface, the electrodes are each supplied with catalysts.
Fuel cells are typically supplied with a continuous flow of reactants from outside the cell. In an alkaline fuel cell the reactants include hydrogen and oxygen. The reaction at the anode is between hydrogen and hydroxyl ions (OH−) present in the electrolyte, which react to form water and release electrons:H2+2OH−⇄2H2O+2e−. At the cathode, oxygen, water, and electrons react in the presence of the cathode catalyst to reduce oxygen and form hydroxyl ions (OH−):O2+2H2O+4e−⇄4OH−. The flow of electrons is used to provide electrical energy for a load externally connected between the anode and cathode.
Stanford Ovshinsky and colleges have made numerous discoveries in the field of material science and more particularly in the filed of disordered and amorphous materials, some of which are described in U.S. Pat. No. 4,430,391 entitled “Fuel Cell Cathode” issued Feb. 7, 1984; U.S. Pat. No. 4,537,674 entitled “Electrolytic Cell Anode” which issued Aug. 27, 1985; and U.S. Pat. No. 5,840,440 entitled “Hydrogen Storage Materials Having A High Density of Non-Conventional Useable Hydrogen Storing Sites” issued Nov. 24, 1998.
As taught by Ovshinsky, disorder in a modified material can be of an atomic nature in the form of compositional or configurational disorder provided throughout the bulk of the material, in various regions or phases of the material, or in the surface of the material. Disorder can also be introduced into the host matrix by creating phases of intermediate order within the material which mimic the compositional or configurational disorder at the atomic level by virtue of the relationship of one phase to another.
Disorder can be tailored by introducing microscopic regions or phases of different kinds, such as crystalline phases, or by introducing regions of amorphous material, or by introducing regions of amorphous material in addition to crystalline regions. Disorder can provide local structural chemical environments with improved characteristics by selecting elements which by their orbital interaction can create new and improved local environments. These specialized local environments may be provided by amorphous materials, microcrystalline materials, multi-component, multiphase, polycrystalline materials, multi-component, multiphase, polycrystalline materials lacking long range composition order, materials of intermediated order, microcrystalline phases, nanocrystalline phases, and/or multiphase materials containing both amorphous and crystalline phases.
Short-range, or local order has been elaborated by Ovshinsky in U.S. Pat. No. 4,520,039, entitled Compositionally Varied Materials and Method for Synthesizing the Materials, the contents of which are incorporated by reference. This patent teaches that disordered materials do not require periodic local order and that spatial and orientational placement of similar or dissimilar atoms or groups of atoms is possible with such increased precision and control that the local configurations can be engineered to produce qualitatively new phenomena. The elements of these materials offer a variety of bonding possibilities due to the multidirectionality of f-orbitals, d-orbitals or lone pair electrons. The multidirectionality (“porcupine effect”) of d-orbitals provides for a tremendous increase in the spectrum and the density of chemically active sites. However, the types of atoms need not be restricted to “d band” or “f band” atoms, but can be any configuration in which the controlled aspects of the interaction with the local environment and/or orbital overlap plays a significant role physically, electronically, or chemically so as to affect physical properties, and hence the functionality of the materials. Following these teachings, one can synthesizing new materials which may even have the same chemical composition, but in fact provide substantially different physical properties.
Despite the above advances provided in the past, alkaline fuel cells have not found wide commercial acceptance due to the competing use of fossil fuels and the internal combustion engine. Therefore, to bring fuel cells to the forefront of wide scale commercial practicality, what is needed is an improved, high efficiency catalytic material useful in fuel cells that can be mass produced at a relatively low cost.